The present invention relates to a method of identifying, for a patient having pain of a joint, susceptibility to developing progressive osteoarthritis or loss of joint space (change in cartilage of the joint) by determining in such patient the presence or absence of bone marrow edema about the joint. A determination of the presence of bone marrow edema about the joint identifies the patient as susceptible to developing progressive osteoarthritis or loss in joint space.
Osteoarthritis is the most common form of arthritis, affecting the hands, knees, hips, spine and other joints. Characteristics of osteoarthritis include a loss of cartilage, seen as a reduction in the joint space, and osteophytes (marginal lips of bone that grow at the edges of the joints). Other forms of arthritis are also characterized by joint space loss.
Predictors of which patients will have progressive osteoarthritis, and which will have stable, non-progressive diseases is lacking, except for the use of bone scintigraphy in predicting joint space loss in the knee. However, repeated scintigraphy is not viable for following patients because of the associated repeated ionizing radiation dose. Other forms of arthritis also may have joint space loss, the prediction of which is also difficult to do or not able to be determined.
An object of the present invention is a non-invasive method, without the use of ionizing radiation, for predicting which patients are likely to have progressive osteoarthritis or joint space loss. Such a method is useful for determining which patients should receive joint protective therapies to preserve joint function.
It has been discovered that finding bone marrow edema about or of a joint of a patient is predictive of the patient developing progressive osteoarthritis in the joint. In particular, it has been found that bone marrow edema about or of a joint of a osteoarthritis patient is predictive of rapid loss of joint space width in the joint of the patient.
Accordingly, the present invention relates to a method of identifying, for a patient having pain of a joint, susceptibility to developing progressive osteoarthritis or joint space loss. The method comprises (a) performing on the patient an assay for the presence or absence of bone marrow edema about or of the joint and (b) determining in such patient the presence or absence of bone marrow edema about or of the joint. A determination of the presence of bone marrow edema about or of the joint identifies the patient as susceptible to developing progressive osteoarthritis or joint space loss.
Magnetic Resonance Imaging (MRI) is a non-invasive cross sectional imaging technique that uses magnetic fields and radio frequencies, and no ionizing radiation, to produce images of the body with excellent anatomic fidelity and soft tissue evaluations. Using specific combinations of magnetic fields and radio frequencies (pulse sequences), specific soft tissue changes can be seen, for example, the presence of water in the bone marrow about the knee.
As used herein, xe2x80x9costeoarthritisxe2x80x9d means a non-inflammatory or minimally inflammatory arthritis in which there is degeneration of articular cartilage, thickening, erosion and subarticular cyst formation of the underlying subchondral bone, and production of reactive marginal osteophytes about the joint, leading to deformity from joint destruction.
As used herein, xe2x80x9cjoint space lossxe2x80x9d means a continued loss or increased abnormality of cartilage (commonly associated with joint space loss).
As used herein, xe2x80x9cprogressive osteoarthritisxe2x80x9d means a continued loss of cartilage (commonly with joint space loss) and bone stock, as well as the increase in marginal osteophytes, subchondral bone hardening/thickening, and the onset or increase of subchondral cysts, as well as other findings known to occur with osteoarthritis. These changes may occur simultaneously or the changes may be distributed about time and areas about the joint in an uneven manner.
As used herein, xe2x80x9cbone marrow edemaxe2x80x9d means increased water content within the bone marrow space above that in normal bone marrow.
As used herein, xe2x80x9carea about or of the jointxe2x80x9d, for a given joint, is an area about 1 to 20 cm above and 1 to 20 cm below the articulating surface(s) of the given joint, the actual useful range dependent on the size of the joint examined.
In a preferred embodiment, the assay for the presence or absence of bone marrow edema about or of the joint is by MRI, in particular, an MRI method or pulse sequence or imaging orientation that provides imaging of the joint area where bone marrow edema can be visualized. Any MRI technology where bone marrow edema can be evaluated can be used, for example, open MRI, low field strength MRI, extremity MRI, whole body scanner MRI or the like. Other methodologies that allow for the determination of bone marrow edema would likewise provide similar information and could be used to predict progression of osteoarthritis or loss of joint space.
To determine progression of joint space narrowing, any method that measures joint space width can be used, for example, semi-flexed radiograph (x-ray method). This would also include methods that determine, directly or indirectly, the amount and/or viability of the cartilage of a joint (e.g. ultrasound, arthoscopy, etc.).
The following clinical study example illustrates, without limitation, the present invention.